Fluid flow controlling mechanism



Feb. 28, 1933. J Q D; P NT 1,899,235

FLUID FLOW CONTROLLING MECHANISM Filed May 20. 1950 A V E 5 ii In Patented Feb. 28, 1933 1,899,235

UNITED STATES PATENT OFFICE JAMES Q. DU FONT, OF JOHNSTOWN, PENNSYLVANIA FLUID FLOW CONTROLLING MECHANISM Application filed May 20, 1930. Serial No. 454,129.

This invention relates to fluid flow control- Figure 4 is a section of a detail of the brake ling mechanism and particularly to mechasystem; and nism for automatically reducing or wholly Figure 5 is a longitudinal section throughinterrupting a continuous or alternatin flow, a modified form of valve.

5 of fluid upon the occurrence of a break 1n the In Figure 1 a simple form of theautomatic fluid transmission system. valve is illustrated, the numeral 10 indicating The invention has for its object the proa cylinder and 11 a piston therein. The pisvision, in this connection, of a simple and ton may be biased by a spring 12 to a position' eflective automatically operating valve mechadjacent one end of the cylinder, as shown.

10 anism of general utility but particularly Fluid is adapted to flow into and out of the of value in combination with a hydraulic cylinder through pipes 13 and 14, which brake system for motor vehicles. In the form members of a piping system in which usual four-wheel hydraulic brake systems, fluid is adapted to flow in the direction of the the fluid conduits leading to the respec arrows. The cylinder at its opposite end is 15 tive brake-actuating mechanisms communiformed with a seat 15 which is engaged by cate with each other, generally through the the piston when the latter moves to that end common fluid pressure and supply chamber, of the cylinder, in which event the piston so that, in the event that a leak develops in serves as a cut-off valve preventing further one of the conduits, fluid will be drained flow through the conduit.

from all, thereby rendering the entire brake Assuming that it is desired to limit the system inoperative. In accordance with the quantity of fluid flowing in the system to a present invention, means is inserted in each certain volume, the volume displaced by the of the fluid conduits leading to a brake unit piston in moving from the position shown which is effective to interrupt the flow to the position where it engages the valve through any condfiit'i'fi'WhilTwbreak or seat 15 will be made equal to this desired vol "leakdevelops;' "so that waste of"fluid from urine of flow. Obviously, if there is no leakthe system is prevented and the danger of age of fluid past the piston, when the predethe entire braking system being rendered termined volume of fluid has flowed past any inoperative, obviated. Preferably the two point of the system, the piston will have 30 pairs of conduits leading, respectively, to moved to engage seat 15, thereby interruptthe front and rear wheel brakes are so aring the flow. ranged that a common cut-ofl valve is eflec If it be desired to limit the flow to a pretive to cut out both conduits should a leak determined rate, provision will be made to develop in either, thereby avoiding the pospermit a flow past the piston of suflicient vol- 35 sible bad results of having the brake of one ume to produce the desired rate of flow. This wheel applied while the brake of the companmay be done by providing a clearance beion wheel is not. tween the piston and cylinder wall, by the Certain embodiments of the invention are provision of holes or grooves around the outillustrated in the accompanying drawing, in er edge of the piston, or by providing a by- 40 which: pass around the piston adjustable to efi'ect Figure 1 is a longitudinal sectional view any desired rate of flow. With the valve through a simple form of valve embodying device thus constructed or adjusted to permit, the invention; a given rate of flow, if this rate should be- I, Figure 2 is a similar view showing the exceeded, the piston will move toward the valve in combination with certain auxiliary right-hand end of the cylinder and engage parts; seat 15, stopping further flow. If it is do Figure 3 is a plan outline of portion of a sired to adapt the valve for use in a system motor vehicle having a four-wheel hydraulic having a positively impelled alternating brake system provided with valves constructflow, the cylinder, of course, may be provided ed according to the invention; with a seat at both ends, and the piston may 100 preferably be biased by springs to a position at the mid-point of the cylinder. However, where the device is used to limit a pure alternating flow of fluid (without leakage around the piston in either direction), there is little need of a spring except in the case where the device is so placed that gravity cannot return the piston or unless the alternation or pulsation is so high as to cause a lag or out-of-step effect due to the inertia of the piston. It will also be understood that various other changes and modifications may be made in the device as described and illustrated without departing from the scope of the invention as defined in the claims.

I In Figure 2 the simple form of valve above described is shown in combination with certain auxiliary elements. The construction shown in this figure provides an adjustable by-pass around the piston valve, means for draining the system of fluid, such as air, gas,

etc., and a safety latch adapted to hold the.

piston valve in closed position until manualreleased. Cylinder 10 is formed with a longitudinal passage 18 opening at one end into the rear end of the cylinder back of pistom 11 and opening at its other end into a passage 19 which communicates with pipe 14. Passage 18 is adapted to be closed or to be opened to any desired degree by a needle valve 20 having a stem 21 threaded into a transverse aperture within the front end of the cylinder and extending across passage 19, a bushing 22 being provided to effect a liquid-tight joint between the head of valve stem 21 and the surface of the cylinder. Piston 11 carries on its front end a yielding facing 11 of rubber, or other suitable material, adapted to engage valve seat 15, and also carries at this end an axially projecting spring latch 23 adapted, when the piston has will engage seat 15 and stop further flow,

spring latch 23 snapping over valve stem 21 and locking the piston. The valve will permit any desired rate of flow by adjusting the needle valve in accordance with the rate desired andlor by perfgrating the piston. Pis

ton 11' can be returned to its initial position by unscrewing valve stem 21 until latch 23 is disengaged. This will also fully open bypass 18, equalizing the pressure on opposite ends of the piston and permitting spring 12 to return the piston. .To drain the system of fluid, such as air, gas, etc., it is only necessary to remove the valve stem 21 entirely.

The application of a valve embodying the invention to a four-wheel hydraulic brake system is shown in Figures 3 and 4:- These figures show in a somewhat diagrammatic way a piping system for the brake actuating fluid. Conduits 27 27 and 28, 28 lead, respectively, to the front and rear wheel brakes. These conduits communicate with a cylinder 29 having a piston 30 provided with a rod 31 which is adapted to be depressed for applying the brakes by a pedal operated lever 32. As shown, conduits 27 unite with a pipe 33 communicating with the bottom of cylinder 29, and conduits 28 unite with a pipe 34 also connected to the bottom of the cylinder. In the pipes 33 and 34 are inserted valves V and V, respectively, which may be constructed as shown in Figure 2. i

If a leak should develop in either of the pipes 27 leading to the front wheel brakes, piston 11 of valve V would shut off the connection between both pipes and the pipe 33 connected to cylinder 29 after a predetermined leakage has occurred, thus cutting out the front wheel brakes and preventing leakage of fluid from the pipes 28 leading to the rear wheel brakes and from the cylinder 29, so that the rear wheel brakes would still be operative. Similarly, if a leak should develop in either of the pipes 28, the rear wheel brakes would be out out, but the front wheel brakes would be operative. A valve device could of course, be inserted in each of the pipes 27 and 28, but in such case a leak in one of the pipes would result in rendering only the particular brake connected to that pipe inoperative, leaving the companion wheel brake operative. As this might result in a tendency of the car to swerve upon application of the brakes, it is, therefore, preferred to have both of the front wheel brakes controlled by a single valve device and to have both of the rear wheel brakes controlled by a single independent valve device.

When using the valve device illustrated by Figure 2 for controlling the flow of fluid in the conduits of a hydraulic brake mechanism,

the by-pass 18 would, of course, be entirely closed by needle valve 20 under normal conditions. The feature of the lock for holding i the piston in position to shut off the conduit. 3 in which a leak has occurred is of value as it positively holds the yieldable face 11 of the piston against seat 15 and thereby prevents leakage of oil past the piston from position from an position to which it has moved because 0 small leakage or evaporation of oil in the conduits and brake actuating motors, the by-pass can be opened to effect this result.

It will be understood, of course, that in the ordinary operation of the motor vehicle the brakes are only intermittently operated and that the fluid in the system is only intermittently placed under pressure, so that the several valve pistons in turn are only occasionally urged toward the outlet ends of their respective cylinders. So long as no leak develops in the system, the several valves mere ly move forwardly in their respective cylinders,stoppingbefore coming into contact with the valve seats and returning when the pressure of the fluid is relieved. They therefore merely move forwardly and backwardly idly with the braking fluid, in the normal case, of fering very little opposition to fluid flow-in either direction. It is only when there is an excessive flow, due to a breakorthe-liker that the piston moves to such extent astaact as a cut-off valve, in the manner heretofore described. 1

In Figure 5 a diaphragm type of valve is illustrated. Here the two halves of the cylinder clamp between them a diaphragm 40. Formed in diaphragm 40 is a number of small holes 41, and mounted centrally upon the same is a valve disc 42, adapted to seat upon valve seat 43 when the, diaphragm is flexed materially toward the right (Figure 5). A light spring 44 normally returns the diaphragm to central position, but, in the event that a considerable unbalanced pressure upon the diaphragm causes seating of the valve 42, a latch 45 hooks over a catch 46 so that the valve is secured in seated position. By removing the catch 46, which in this instance is a screw, the latch can be released.

While I have described the valve as particularly useful in connection with motor vehicle braking systems, it will be apparent that it is a device of general utility and may be used in many combinations in the industrial arts. It may in fact be employed whereever it is desired to decrease or shut ofl flow through a conduit in any case where there is an abnormal increase in the velocity of flow therethrough or an abnormal increase in volume of flow.

, Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In combination with an hydraulic braking system for motor vehicles including a conduit connected at one end to the brake operating motor associated with one of the wheels of the vehicle and at its other end to the cylinder of the pedal operated piston, a valve connected in said conduit adjacent said cylinder, said valve comprising a cylinder and a piston therein, the cylinder being provided with" a seat at one end adapted to be engaged by the piston to stop the flow of fluid in said conduit, a by-pass around said piston, a needle valve normally closing said by-pass having a stem screwed into said cylinder at said end, said piston having a spring latch adapted to engage said stem to hold the piston against said seat.

2. A valve including a cylinder adapted for insertion in a piping system for conveying fluid, the cylinder being provided with pipe connections at its two ends respectively, a piston in said cylinder, a spring normally holding said piston adjacent one end of the cylinder, a seat surrounding the opening in the other end of the cylinder adapted to be engaged by the piston, a by-pass around the piston, a needle valve screwed in said other end of the cylinder controlling said by-pass, the stem of the needle valve extending across the opening into the cylinder at this end, and a spring latch carried by the piston adapted to engage sa-id'stem when the piston engages said seat.

3. A valve including a cylinder adapted for insertion in a piping system for conveying fluid, the cylinder being provided with pipe connections at its two ends respectively, a piston in said cylinder, a spring normally holding said piston adjacent one end of the cylinder,- a seat surrounding the opening in the other end of the cylinder, the piston carrying a yieldable facing adapted to engage said seat, a bypass around the piston, a needle valve screwed in said other end of the cylinder controlling said by-pass, the stem of the needle valve extending across the opening into the cylinder at this end, and a spring latch carried by the piston adapted to engage said stem when the piston engages said seat.

4. A fluid flow controlling device including a cylinder adapted to be inserted in a piping.

system for conveying fluid, said cylinder beingprovided with pipe connections at its two ends respectively, a valve member adapted to reciprocate in said cylinder and to close one of said pipe connections upon the occurrence of a predetermined flow of fluid in said system, and means for locking the piston in such position, said means comprising a threaded member adapted to be screwed through an opening in said cylinder at one end thereof and an element carried bysaid valve member and adapted to engage said threaded member.

5. A fluid flow controlling device including acylinder adapted to be inserted in a piping system for conveying fluid, said cylinder being provided with pipe connections at its two ends respectively, a valve member adapted to reciprocate in said cylinder and to close one of said pipe connections upon the occurrence of a predetermined flow of fluid in said system, a drain or relief opening in said cylinder, a plug adapted to be inserted within said opening, and an element carried by said valve member and adapted to engage a portionof said plug, whereby said valve member may be retained in said closed position.

5 6. A fluid flow controlling device including a cylinder adapted to be inserted in a piping system for conveying fluid, said cylinder being provided with pipe connections at its two ends respectively, a valve member 9 adapted to reciprocate in said cylinder and to close one of said pipe connections upon the occurrence of a predetermined flow of fluid in said system, a restricted portion at one end of said cylinder, a retaining member adapted to be removably disposed within said restricted portion, and an element carried by said valve member and adapted to extend into said restricted portion and to engage said retaining member to lock said valve member in said closed position.

7. A fluid flow controlling device including a cylinder adapted to be inserted in a piping system for conveying fluid, said cylinder being provided with pipe connections at its two ends respectively, a valve member adapted to reciprocate in said cylinder and to close one of said pipe connections upon the occurrence of a predetermined flow of fluid in said system, a by-pass conduit adapted to afford communication between the end portions of said cylinder around said valve, a drain or relief opening in said cylinder in the vicinity of one end of said bypass conduit, a plug adapted to close said opening and having a portionadaptcd to control the flow through said by-pass, and an element on said valve member adapted to engage a portion of said plug to retain said valve in said closed position.

8. A fluid flow controlling device including a cylinder adapted to be inserted in a piping system for conveying fluid, said cylinder being provided with pipe connections at its two ends respectively, a valve member adapted to reciprocate in said cylinder and to close one of said pipe connections upon the occurrence of a predetermined flow of fluid in said system, an equalizing by-pass conduit adapted to aflord communication be tween the end portions of said cylinder around said valve, an adjustable member adapted to control the flow through said bypass and an element carried by said valve 55 member adapted to engage said adjustable member to lock said valve member in closed position, means for actuating said adjustable member to release said valve member and to simultaneously open said equalizing bypass.

60 In testimony whereof I hereunto aflix my signature.

JAMES Q. DUPONT. 

